Landforms of erosion Flashcards
What geological formations occur where there are alternating bands of hard and soft rocks?
Headlands and bays
This occurs along a discordant coastline.
What type of rock is typically eroded first to form an inlet?
Softer rock (e.g. clay)
Softer rocks erode backward initially.
What is formed as the inlet continues to erode and curves inwards?
A bay
A bay is usually associated with a beach.
What features characterise a headland?
- Cliffs along its sides
- Projects out to sea
- Usually longer than it is wide
- Geology is of resistant rock
Headlands are formed from harder rock.
What are the typical characteristics of a bay?
- A wide, open entrance from the sea
- A roughly semi-circular shape extending into the coastline
- Land that is lower than the headlands surrounding it
- A bay may or may not have a beach
Bays are formed in the spaces between headlands.
What processes shape cliffs?
Erosion and weathering processes
These processes include various natural forces that wear away rocks.
How do soft rocks affect cliff formation?
Soft rock erodes quickly and will form sloping cliff faces
This results in less steep cliffs compared to hard rock.
What type of cliffs are formed by hard rock facing the sea?
Steep cliffs
Hard rock is more resistant to erosion.
What is a wave-cut platform?
A wide gently sloped surface found at the foot of a cliff
It is formed through the processes of erosion at the base of cliffs.
What forms between the high and low water mark on a cliff?
A wave-cut notch
This notch is created as waves attack the base of the cliff.
What processes extend the wave-cut notch back into the cliff?
Abrasion, solution, and hydraulic action
These processes contribute to the erosion of the cliff face.
What leads to the instability and collapse of a cliff?
The undercutting of the cliff
This occurs as erosion removes material from the base.
What happens to the eroded material carried away by waves?
It is carried away by the backwash of the waves
This process leaves behind a wave-cut platform.
What is the result of the repeated erosion of cliffs?
Coastal retreat
This leads to the gradual movement of the coastline inland.
What natural features form in a headland due to wave action and sub-aerial weathering?
Caves, arches, and stacks
These features are shaped by the erosive forces of waves and weathering processes.
What happens to waves as they approach the shore?
Their speed is reduced as they move along the sea floor
This speed reduction alters the angle of the waves.
What is wave refraction?
The turning of waves so the crest becomes parallel to the coast
This process concentrates erosive action on the headland.
What erosional processes attack weaknesses in a headland?
- Hydraulic power
- Abrasion
- Corrosion
These processes work together to erode the headland.
What occurs as the crack in a headland widens?
Abrasion begins to wear away at the forming cave
This leads to the development of a larger cave.
What forms when a cave breaks through the headland?
An arch
The arch is a result of continued erosion and widening.
How does the base of an arch change over time?
It becomes wider and thinner through erosion below and weathering from above
This process contributes to the eventual collapse of the arch.
What is left behind after the roof of an arch collapses?
An isolated column of rock called a stack
The stack is a significant feature in coastal landscapes.
What processes continue to affect a stack after its formation?
It is undercut at the base by wave action and sub-aerial weathering above
These processes can lead to the stack’s eventual collapse.
What forms after a stack collapses?
A stump
The stump is the final stage of erosion from the original headland.
